Recipe Scaling - Time & Pressure?

[coffee joe]

I had thought I knew what was going on in my pressing, now new doubts.

Here is what I thought was right

Pressure (PSI) on the "follower"should always be maintained the same for similar results.

The weight needed to achieve this, needs to go up if it is a rock on top of a wider "follower"

When I moved from a 6" form to an 8 " form I would need to multiply by 1.77 the weight of the rock so a 50LB rock that worked well on my 6" form would need to be an 88 lb rock for the same pressure (PSI)

Have I missed something?

[MarkShelton]

That's right according to my calculations.

50lbs per ~28sq in = 88lbs per ~50sq in

[DeejayDebi]

Sounds right to me just remember it's square inches = surface area not volume or cubic inches